      *> File Name     000002_Boolean.cbl.
      *> Description   A first introduction to Value types and the
      *>               generic System.Nullable type.
      *> Project Type  Console Application.
      *> CodePlex URL  http://cobol.codeplex.com

      *> Comments      See also 000013_NativeTypes.cbl.

       program-id.   Main.
       repository.
           class sys-console as "System.Console"
           .
       working-storage section.
       01  b   condition-value.
       01  nb  type "System.Nullable"[condition-value].
       procedure division.
           move "Value Types and the Generic System.Nullable Type"
               to sys-console::"Title"
 
           set b to false
           display "Boolean b is " b "."
 
           set nb to NULL
           if nb::"HasValue" then
               display "Nullable boolean nb is " nb "."
           else
               display "Nullable boolean nb is null."
           end-if
 
           display "Press any key to continue . . . " no advancing
           invoke sys-console::"ReadKey"(true)
           .
       end program   Main.
